This application relates to the art of thermal cutoffs and, more particularly, to thermal cutoffs for protecting electric circuits. The invention is particularly applicable for use with thermal cutoffs of the type having a meltable thermal pellet, and will be described with specific reference thereto. However, it will be appreciated that the invention has broader aspects, and can be used with other types of thermal cutoffs.
Resistor wire or etched foil elements have been positioned in surrounding relationship to thermal cutoffs for heating same to the firing temperature. These arrangements are relatively expensive, and it is also difficult to control the heating rate. It would be desirable to have a low cost arrangement for providing a thermal cutoff with an external heater whose heating rate can be controlled.